The present disclosure relates to thermoplastic polycarbonate compositions having improved heat resistance. In particular, the disclosure relates to such polycarbonate compositions having improved heat resistance, impact performance, and flow properties. Also included are methods for preparing and/or using the compositions, such as forming articles therefrom.
Polycarbonates (PC) are synthetic thermoplastic resins derived from bisphenols and phosgenes, or their derivatives. They are linear polyesters of carbonic acid and can be formed from dihydroxy compounds and carbonate diesters, or by ester interchange. Polymerization may be in aqueous, interfacial, or in nonaqueous solution. Polycarbonates are a useful class of polymers having many desired properties. They are highly regarded for optical clarity and enhanced impact resistance and ductility at room temperature or below.
Impact modifiers are incorporated into polymeric resins to improve the impact strength of finished articles made from such resins. Exemplary impact modifiers include acrylonitrile-butadiene-styrene (ABS) and methacrylate-butadiene-styrene (MBS) polymers. ABS and MBS polymers are synthetic thermoplastic resins made by polymerizing acrylonitrile or methacrylate, respectively, with styrene in the presence of polybutadiene. The properties of ABS; and MBS can be modified by varying the relative proportions of the basic components, the degree of grafting, the molecular weight, etc. Overall, ABS and MBS are generally strong, and lightweight thermoplastics.
Blends of polycarbonates with ABS or MBS, or PC/ABS or PC/MBS blends, are also well-known. For example, SABIC Innovative Plastics provides such blends commercially under the brand name CYCOLOY®. These amorphous thermoplastic blends have many desired properties and/or characteristics, including high impact strength, heat resistance, good processability, weather and ozone resistance, good ductility, electrical resistance, aesthetic characteristics, etc. They are widely used in the automotive market, for producing appliance and electrical components, medical devices, and office and business equipment such as computer housings, etc.
There remains a need in the art for thermoplastic polycarbonate compositions having improved heat resistance and chemical resistance. Desirable features of such materials include, among others, excellent mechanical properties, ease of manufacture, and transparency.